// Copyright (c) 2011-2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_QT_PAYMENTSERVER_H
#define BITCOIN_QT_PAYMENTSERVER_H

// This class handles payment requests from clicking on
// bitcoincash: URIs
//
// This is somewhat tricky, because we have to deal with the situation where the
// user clicks on a link during startup/initialization, when the splash-screen
// is up but the main window (and the Send Coins tab) is not.
//
// So, the strategy is:
//
// Create the server, and register the event handler, when the application is
// created. Save any URIs received at or during startup in a list.
//
// When startup is finished and the main window is shown, a signal is sent to
// slot uiReady(), which emits a receivedURI() signal for any payment requests
// that happened during startup.
//
// After startup, receivedURI() happens as usual.
//
// This class has one more feature: a static method that finds URIs passed in
// the command line and, if a server is running in another process, sends them
// to the server.
//

#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif

#ifdef ENABLE_BIP70
#include <qt/paymentrequestplus.h>
#endif
#include <qt/walletmodel.h>

#include <QObject>
#include <QString>

class OptionsModel;

QT_BEGIN_NAMESPACE
class QApplication;
class QByteArray;
class QLocalServer;
class QNetworkAccessManager;
class QNetworkReply;
class QSslError;
class QUrl;
QT_END_NAMESPACE

// BIP70 max payment request size in bytes (DoS protection)
static const qint64 BIP70_MAX_PAYMENTREQUEST_SIZE = 50000;

class PaymentServer : public QObject {
    Q_OBJECT

public:
    // Parse URIs on command line
    // Returns false on error
    static void ipcParseCommandLine(interfaces::Node &node, int argc,
                                    char *argv[]);

    // Returns true if there were URIs on the command line which were
    // successfully sent to an already-running process.
    // Note: if a payment request is given, SelectParams(MAIN/TESTNET)  will be
    // called so we startup in the right mode.
    static bool ipcSendCommandLine();

    // parent should be QApplication object
    explicit PaymentServer(QObject *parent, bool startLocalServer = true);
    ~PaymentServer();

    // OptionsModel is used for getting proxy settings and display unit
    void setOptionsModel(OptionsModel *optionsModel);

#ifdef ENABLE_BIP70
    // Load root certificate authorities. Pass nullptr (default) to read from
    // the file specified in the -rootcertificates setting, or, if that's not
    // set, to use the system default root certificates. If you pass in a store,
    // you should not X509_STORE_free it: it will be freed either at exit or
    // when another set of CAs are loaded.
    static void LoadRootCAs(X509_STORE *store = nullptr);

    // Return certificate store
    static X509_STORE *getCertStore();

    // Verify that the payment request network matches the client network
    static bool verifyNetwork(interfaces::Node &node,
                              const payments::PaymentDetails &requestDetails);
    // Verify if the payment request is expired
    static bool verifyExpired(const payments::PaymentDetails &requestDetails);
    // Verify the payment request size is valid as per BIP70
    static bool verifySize(qint64 requestSize);
    // Verify the payment request amount is valid
    static bool verifyAmount(const Amount requestAmount);
#endif

Q_SIGNALS:
    // Fired when a valid payment request is received
    void receivedPaymentRequest(SendCoinsRecipient);

    // Fired when a message should be reported to the user
    void message(const QString &title, const QString &message,
                 unsigned int style);

#ifdef ENABLE_BIP70
    // Fired when a valid PaymentACK is received
    void receivedPaymentACK(const QString &paymentACKMsg);
#endif

public Q_SLOTS:
    // Signal this when the main window's UI is ready to display payment
    // requests to the user
    void uiReady();

    // Handle an incoming URI, URI with local file scheme or file
    void handleURIOrFile(const QString &s);

#ifdef ENABLE_BIP70
    // Submit Payment message to a merchant, get back PaymentACK:
    void fetchPaymentACK(WalletModel *walletModel,
                         const SendCoinsRecipient &recipient,
                         QByteArray transaction);
#endif

private Q_SLOTS:
    void handleURIConnection();
#ifdef ENABLE_BIP70
    void netRequestFinished(QNetworkReply *);
    void reportSslErrors(QNetworkReply *, const QList<QSslError> &);
    void handlePaymentACK(const QString &paymentACKMsg);
#endif

protected:
    // Constructor registers this on the parent QApplication to receive
    // QEvent::FileOpen and QEvent:Drop events
    bool eventFilter(QObject *object, QEvent *event) override;

private:
    // true during startup
    bool saveURIs;
    QLocalServer *uriServer;
    OptionsModel *optionsModel;

    bool handleURI(const CChainParams &params, const QString &s);

#ifdef ENABLE_BIP70
    static bool readPaymentRequestFromFile(const QString &filename,
                                           PaymentRequestPlus &request);
    bool processPaymentRequest(const PaymentRequestPlus &request,
                               SendCoinsRecipient &recipient);
    void fetchRequest(const QUrl &url);

    // Setup networking
    void initNetManager();

    // Used to fetch payment requests
    QNetworkAccessManager *netManager;
#endif
};

#endif // BITCOIN_QT_PAYMENTSERVER_H
